Plant PPFD Quantum Sensor
Professional measurement system solutions
Plant PPFD Quantum Sensor
In plant factories and greenhouses, light quantum probes are used instead of ordinary illuminance meters or radiometers because plant photosynthesis and human vision use fundamentally different "languages". Illuminance (Lux) mimics human sensitivity to green light—high readings do not mean plants can use the light effectively. Plant optics (quantum, µmol/m²/s) focuses on photons absorbed by chlorophyll to trigger photosynthesis—we need to know how many photons hit the leaves per second (PPFD), not how bright it looks. The PPFD-100 quantum sensor measures 400-700nm PAR, compliant with GB/T 35139-2017, and can be networked to measure PPFD at each grid point.
Quantum probes address "photon energy non-equivalence": per Planck's law, blue photons have ~30% more energy than red; at equal energy, red produces far more photons—radiometers may show equal values, but PPFD from red lamps far exceeds blue. Only quantum probes reflect the true "raw material" supply for photosynthesis. Modern plant lighting uses red-blue or full-spectrum LEDs; high-quality probes use PAR response filters to match 400-700nm theory for accurate readings in any spectrum. PPFD-100 has cosine-corrected head for accurate multi-angle measurement; integrates with PLC or environmental control for on-demand supplemental lighting and energy savings.
Key Features
- Plants need photon count, not brightness: PPFD (µmol/m²/s) reflects photons per second on leaves; illuminance meters cannot accurately assess plant PAR
- Photon energy non-equivalence: blue vs red photon energy differs; quantum probes reflect true photosynthetic "raw material"; radiometers can misjudge
- Complex spectrum adaptation: red-blue or full-spectrum LED; PAR filter ensures 400-700nm match; accurate in any spectrum
- PPFD-100: cosine-corrected head, 400-700nm response, networkable for grid PPFD; GB/T 35139-2017 compliant
Core Application Scenarios
PPFD Verification - Light Intensity Compliance
After luminaire installation, use quantum probe for point-by-point measurement on cultivation surface to verify PPFD min, max and uniformity against crop requirements; avoid etiolation from insufficient light or photoinhibition from excess.
DLI Calculation - Daily Light Integral Monitoring
Continuous monitoring reveals daily photon absorption. Supplement light when overcast; shade or shorten supplemental lighting when summer light is excessive for energy saving.
Smart Supplemental Lighting - Closed-Loop Control
Connect probe to PLC or environmental control; when natural light is insufficient and PPFD falls below threshold, automatically enable supplemental lighting; when PPFD is met, automatically turn off for on-demand lighting and significant energy savings.
Measurable parameters
Technical specifications
- PPFD-100 quantum sensor: cosine-corrected head for accurate measurement of light from all angles;
- Wavelength response: strictly covers 400-700nm PAR band;
- Networkable: measure PPFD at each grid point for cultivation surface verification;
- PLC or environmental control integration: closed-loop feedback for automatic supplemental lighting when PPFD below threshold.
